#!usr/bin/env python
# -*- coding:utf-8 _*-
"""
@author:zhengxin
@file: 021_score_sequence.py
@time: 2024/12/19  10:50
# @describe:
"""

'''
    有一分数序列：2/1，3/2，5/3，8/5，13/8，21/13...求出这个数列的前20项之和
'''
def score_sequence():
    a, b, num = 2, 1, 0
    for i in range(20):
        num += a/b
        a = a+b
        b = a-b
    print(num)